Pump priming system



PUMP PRIMING SYSTEM Filed Aug. 9,1945

HEAT EXCHANGE 0/5351. ENG/NE awe/rm EDWARD (J. LLOYD Patented Oct. 7, 1947 rum mmmo SYSTEM Edward 0. Lloyd, Silver Spring, Md.

Application August 9, 1945, Serial No. 609,905

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'10 '0. G. 757) 9Claims.

This invention relates to a priming system for dual pump installations, and has for its principal object the provision, for one pump of such an installation, of an automatic priming system of improved reliability not dependent upon external or indirect'sources of power for its operation.

The use of eductors for priming pumps has been generally accepted when manual operation of the priming systems is permissible. A common arrangement of this device for pump priming provides an external supply of water under pressure to operate the eductor. which is connected by suitable piping to evacuateair and vapor from the pump and a check valve installed adjacent to the pump discharge to prevent air from entering the pump during the priming operation. When automatic priming is required, the use of separate vacuum pumps or the use of booster pumps is oftenresorted to. Vacuum pumps are usually installed with pip'lng connections similar to those used for an eductor; the vacuum pump, however, requires no external supply of water under pressure, but requires a power supply for its operation. Booster pumps are usually installed in a location that insures a gravity supply of water to the booster pump, and connected to discharge water continuously to the pump requiring priming. An electric motor is commonly used to drive the booster pump.

It is therefore an object of the present invention to overcome, in the case of dual pump installations, the disadvantages inherent in systems such as those described above, and in particular to provide a system having the maximum obtainable reliability of operation, but of minimum complexity and requiring a minimum quantity of equipment. A further obj ct is to provide a priming system for dual pump installations wherein the operation of the priming. systems will not result in admixture of the fluid normally pumped by one pump with the fluid normally pumped by the other pump.

In order to make the invention more clearly understood, there is shown in the accompanying drawing one embodiment of means for carrying the invention into practical use, without limiting the improvements in their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of illustration.

The single figure of the accompanying drawing is a view showing an end elevation of a marine internal combustion engine having two centrifugal pumps used in the operation of the en- 2 gine cooling system, wherein a portion of the water discharged from the jacket water pump is usedto automatically prime the sea water pump.

In this drawing is illustrated a Diesel engine having a jacket water pump I and a sea water or raw water pump 2. The jacket water pump is shown connected in a conventional manner to draw jacket water from a heat exchanger 23 by means of pipe 3 and to discharge the water to the engine cooling passages by means of jacket water discharge pipe 4. From the engine cooling passages the jacket water'returns via pipe 24 through the heat exchanger to pipe 3 and to the jacket water pump. Surge tank 5 is connected to the. jacket water system through pipe 6 and functions, in part, to maintain the jacket water system, including the jacket water pump. heat exchanger, engine cooling passages, and the pip-v ing, completely filled. The sea water pump 2 draws Water through .the sea water suction pipe I from a source of water, the surface level of which may be below the pump, and discharges water through check 'valve 9 and waterdischarge pipe 8 to the heat exchanger.

The priming system is comprised as follows: a pressure responsive valve i0 so constructed that application of pressure from pipe 2! on diaphragm 2i closes the valve, the valve maintain! ing an open position when pressure is not so applied; a water jet eductor II is so arranged that the lateral suction created by a jet of water supplied through eductor actuating pipe l6 acts to evacuate the priming pipe 20, the fluid so evacuated being discharged with the actuating water through eductor discharge pipe II; 'a float operated valve I! so constructed that the valve is closed by the action of liquid entering and filling the valve chamber, the valve maintaining an open. position when liquid is not so present;

and arranged to permit flow in the 'manner' These various items are connected by shown. pipes i6, l1, l8, I9, 20 and 2!.

The operation of the apparatus is as follows. Upon starting the engine the jacket water pump will immediately function to force jacket water around the closed jacket system. Sea water pump 2 may, however,-fail to draw water unless the pump casing is filled. In this event the sea water pump will fail to create a pressure in the sea 3 water discharge pipe, no pressure will be applied to pressure responsive valve ID by means of the pressure actuating pipe 2| and diaphragm 2i and valve III will remain in an open position. Failure ofthe pressure responsive valve to close will allow a portion of the water, discharged from.

the jacket water pump, to pass through eductor H into the surge tank and return to the jacket waterpump via pipes. The eductor, when so actuated, will evacuate air from sea water pump 2 and the sea water suction pipe 1 through pipe l8, float valve I2, pipe l9, tank i3, pipe 20, check valve i 5 and discharge the air to the atmosphere via the surge tank and vent 22. During this operation, check valve 9 will prevent air from enterlng sea water pump 2 from sea water discharge pipe 8. Evacuation of the air from sea water and suction pipe will continue until the pump is primed and creates suflicient pressure in the pressure actuating pipe 2| to close valve ill thus stopping the flow of jacket water through eductor ll, thereby stopping the priming action. Check valve l5 will then prevent the sea water pump from drawing air through the priming pipe 28.

In the event that valve l0 does not close before sea water is drawn into the float valve, the float valve will close thus preventing the flow of water from the sea water system to the jacket water system. If, during subsequent operation the sea water pump loses prime, the pressure responsive valve will open and the priming operation will be repeated automatically. Tank l3 provides a reservoir to trap small amounts of water that may leak past the float valve. Means for detecting such leakage is provided by level indicator M.

In the embodiment herein described and claimed a particular arrangement applicable to a dual system, has been defined. Other arrangements, using equivalent equipment, could obviously be used and such are intended to be included within the scope and spirit of this invention.

The invention described herein maybe made or used by or for the Government of the United States for governmental purposes without the payment to me of any royalties thereon or therefor.

What is claimed is:

l. A priming system for a pump driven by an internal combustion engine provided with a jacket water pump aiso driven by the engine, comprising an eductor through which water is forced by the via a passage connecting the first said pump and the eductor, means to prevent flow of fluid into thefirst said pump through its outlet and meansfirst said pump. adapted to control the flow of water between the jacket water pump. and the eductor.

. jacket water pump, the eductor being adapted to evacuate air and vapor from the first said pump 3. The priming system of claim 1 comprising also a valve responsive to the position or the liquid level in said passage. adapted, in said passage, to prevent the flow of liquid from the first said pump to the eductor.

4. The priming system 01- claim 1 comprising also a valve, responsive to the pressure in first said pump, adapted to control the flow of water between the jacket water pump and the eductor, and a valve responsive to the position of the liquid level in said passage, positioned in said passage and adapted to prevent the flow of liquid from the first said pump to the eductor.

5. In a priming system for a first pump having a fluid cooled internal combustion engine as motive power, an eductor, a second pump driven by said engine for circulating engine cooling fluid from said second pump to said eductor, and a passage connecting said eductor to said'flrst pump to evacuate air therefrom.

6. In a priming system for a flrst pump having a fluid cooled internal combustion engine as motive power, a second pump driven by said engine for circulating engine cooling fluid, an eductor for priming said first pump. means adapted to conduct a portion of the cooling fluid a of said flrst pump to prevent leakage of air into the pump while priming.

8. A priming system as claimed in claim 6 and a valve in said passage adapted to prevent passage of water therethrough when said flrst -pump is primed.

9. A priming system-as claimed in claim 6, i

and a check valve in said passage adapted to prevent a reverse flow therethrough to said first pump when said eductor is not operating.

EDWARD c. LLOYD;

REFERENCES crrsn The following references are of record in the file of this patent:

UNITED STATES PATENT Number Name Date 1,147,401 Huttner July 20, 1915 1,745,257 Haentjens Jan. 28, 1930 2,235,973 Adney Mar. 25, 1941 FOREIGN PATENTS Number Country Date Germany May 19, 1926. 

